02110nas a2200229   4500008004100000022001400041245012000055210006900175260007500244300001200319490000700331520122900338653001901567653002301586653002201609653003301631653002501664100001701689700002101706700002401727856012901751       2009                        eng d  a1571-101300aSolid acid catalysts: modification of acid sites and effect on activity and selectivity tuning in various reactions0 aSolid acid catalysts modification of acid sites and effect on ac  a233 SPRING ST, NEW YORK, NY 10013 USAbSPRINGER/PLENUM PUBLISHERScSEP  a205-2200 v133 a<p>The effects of acidity and variation in concentration of acid sites of dodecatungstophosphoric acid (DTP), supported DTP and montmorillonite-K catalysts were studied for various organic reactions such as the hydroxyalkylation of phenols to bisphenols, intramolecular rearrangement of benzyl phenyl ether (BPE) to 2-benzyl phenol (2-BP) and selective cleavage of tert-butyldimethylsilyl (TBDMS) ether into the corresponding alcohol. Both dodecatungstophosphoric acid (DTP) impregnated on silica (SiO(2)) and montmorillonite catalysts showed the highest catalyst activity with 90-95% selectivity to bisphenol for the hydroxyalkylation of phenols to give bisphenol. Temperature Programmed Desorption (TPD) of ammonia and activity results of various catalysts showed that an appropriate combination of both strong and weak acidic sites in the catalyst was highly desirable for high bisphenol selectivity. A 10% DTP/SiO(2) catalyst was found to be highly selective for the cleavage of TBDMS ether into the corresponding alcohol at room temperature giving a high TON of 9.5 x 10(5) even after the 4th recycle. DTP was also found to be a promising solid acid catalyst for the intramolecular rearrangement of BPE giving 2-BP.</p>10aAcidity tuning10aCatalytic cleavage10aHydroxyalkylation10aIntramolecular rearrangement10asolid acid catalysts1 aRode, C., V.1 aGarade, Ajit, C.1 aChikate, Rajeev, C.  uhttps://library.ncl.res.in/content/solid-acid-catalysts-modification-acid-sites-and-effect-activity-and-selectivity-tuning-0